markfagus

Hi guys.
1988 4Runner 3.0 auto
270k miles, engine rebuilt at 258k with new timing belt.

In the fall I had an issue where the 4Runner would not start right away. it just cranked and cranked but finally after about 5 minutes she fired up and ran fine and has been running fine ever since.

Yesterday went out to start it and same thing, just cranked and cranked but would not start.
Went out this morning checked relay and it was working fine, checked fuses and all were good. put battery on the charger since I had run it down some.
Figured I would pull the codes no codes.
I tried to start again while the paperclip was still jumping (forgot it was still in) and what do ya know, she fired up and ran fine. Pulled it into the garage to finish recharging battery. Turned it off, tried to restart and she immediately fired right up and idled perfectly like she normally does.

I am scratching my head on this one. Anybody have any clue as to what I have going on?
Like I mentioned, I had this issue back in the fall and she eventually fired up. Have had no issues since then (until yesterday) and have logged approx 5k miles since then.

Help...


Mark

93toyrunner2

With the jumper in, you are turning on the fuel pump, bypassing the normal circuit. Download a copy of the fsm or use the online version (link in my signature), and start by using the "MFI Diagnostics" to find your problem. Possible usual problems - COR, fuel pump

markfagus

Thanks Bob, I will definitely check it out. Once I removed the jumper I shut it off and restarted and it fired right up without it in. And I just tried it again now and fired right up.

Any thoughts on that? does that change what you think?


Mark

93toyrunner2

Sounds like a loose connection somewhere. Check your grounds at the battery sidewall area, at the firewall to the engine. Check your connections at the fuel pump - lift pass side rear seat up and out of way, remove 3 screws in the inspection panel, and look at the connections to the fuel pump, checking for corrosion, clean as necessary.

Outsane

Try it again with the jumper sounds like its still the issue

markfagus

As Outsane suggested I ran the diagnostic again. Started and idles just fine.

Getting a code 12 which is the RPM signal system.

It also says the diagnosis is: No G or NE signal –is input to the ECM for 2 secs. or more after STA turns 4N.

Trouble area list:
* Open or short in NE, G circuit
* Distributor
* Open or short in STA circuit
* ECM

Can someone smarter than me translate what this all means?

Mark

Outsane

You have a short going to your Circuit Opening relay, or COR...

You have two inputs to tell the fuel pump to turn on, one is the, black wiring going to the COR which is energized when trying to start the the engine, after the engine starts the AFM flap opens up and takes over and sends a signal to COR to power the fuel pump..


Here is the wiring diagram for a 85, I don't think the COR wiring is much different..




ps.. my rig is doing the same thing...

markfagus

Thanks man, this is extremely helpful. I will start tracking it down.
In my experience having a short is a condition that happens all the time.
Why do you think it you prevent the truck from starting then all of a sudden acts fine?

Thanks.

Mark

Outsane

Because there is trill fuel pressure in the system

markfagus

Makes perfect sense, until I have a chance to dig in is there a way to "maintain" fuel pressure?
I use this truck as my daily driver and use it to take my 3 year old to day care. I really dont want to experience a no start situation with him in the car with me.

thanks

Mark

Outsane

keep the jumper wire in...

till you can fix it, I think there are a lot of others who do this.. including 4crawler (Rodger)

markfagus

Great, will leaving the jumper wire in do any damage? Just wondering if there is a clock ticking on this fix.

Thanks for ALL the guidance!

Mark

Outsane

I think it will be ok

markfagus

As a thought, could I leave it without the jumper cable and just carry it with me if needed? meaning if I am somewhere for a while and it wont start, can I pop it the jumper cable to create the pressure I need to get it started and then remove it after it is running?

Mark

Outsane

That works